Monday, December 27, 2010

Musings on Metabolism

I recently came across this short article in the New York Times, entitled "Nigeria: Those Born During Biafra Famine Are Susceptible to Obesity, Study Finds", which describes how the children of those who were born to women starving during a country-wide famine have grown up to be more likely to suffer from obesity than those born of women who had enough to eat during their pregnancies. This article got me thinking: did the mother's starvation trigger a metabolic change in the foetus, in other words, was the foetus's metabolism slowing down in order to conserve as much fat (an energy source) as possible in order to survive? I'm not a scientist, but I think this is about as good as hypothesis as any, especially in view of the masses of anecdotal evidence showing how dieting messes with your metabolism and sets you up for a lifetime of starvation in a quest to maintain a lower body weight.

When the body is radically undersupplied with the number of calories it needs to maintain a steady weight, it does not perceive this as simply a "diet". The mind may think it is acting reasonably by controlling calories ingested and burning additional calories through exercise (dieting) while the perfectly designed body--working only on the instinct to survive--fails to distinguish between starvation pure and simple and this "diet".

Since the body only recognizes a state of starvation or a state of non-starvation, what does it do when it notices that it is starving? Simple: it goes into energy conservation mode. It seeks to protect what is most precious to its survival--fat--while using up the "less important" muscle stores. The human body is a master at adapting. Fewer calories in? Let's burn fewer calories since we're under attack and in danger of dying of starvation. That's the metabolism story. I suspect that's also the story of the obese Biafran adults of today.

A perfect example of how metabolism adapts (read: slows down) can be found below in Andrea's story (quoted with permission from Andrea in a response to a post on Debra's Just Maintaining):

It’s decidedly unfun to have regained 25 lbs. (of a 49 lb. weight loss) over the past two years while eating “moderately,” “intuitively,” and “healthfully,” and while exercising 5-6 days a week doing a combination of step aerobics, hi/lo aerobics, and pretty intense strength training, all done to the DVD workouts of the most advanced instructors in the industry (cardio done on all exercise days, strength sessions 3x/week -total exercise time per week 5-6 hours).

I swear I have read AND implemented all the recommendations and I just cannot maintain the weight loss without RESTRICTING my food intake and UNDEREATING. But, if I do that for too long, the “EAT” impulses get very strong and I eventually succumb. I would actually get “EAT NOW” impulses in the middle of the night and couldn’t fall back to sleep until I ate something, which was usually a piece of grilled chicken leftover from dinner or some reduced fat cheese or sliced turkey breast. It was crazy! Trust me, standing in front of an open refrigerator jamming Pollyo part-skim mozarella sticks into your mouth at 3am is really pretty cuckoo. Thankfully those episodes have stopped since I’ve gained weight.

Lest anyone think I had dieted myself to underweight, that wasn’t the case. I’m 5’6″, lost down to 147 lbs. and I’m now at 172 lbs. I don’t eat processed foods of any kind, I don’t eat out in restaurants, I cook all my meals from scratch, I eat a Meditteranean style diet, I eat tons of fresh vegetables and fruits (produce bill is outta control!), I don’t stuff myself, I don’t eat sweets AND I exercise vigorously. It drives me crazy that it’s assumed that I somehow didn’t make the necessary “lifestyle changes” because if I did I wouldn’t have regained.

The biggest myth we are fed (pardon the pun) is that once we have reached the magic number and have made those "lifestyle changes", we will be able to eat "normally". By normally, I mean eating the number of calories that your height, (new, reduced) weight and exercise expenditure should allow you to eat without regaining. Time and time again, people find that this just isn't true. Like Andrea (and Debra and countless others), they must continue to "undereat", stingily meting out a low-calorie diet to their mildly starving bodies for the rest of their lives to maintain the hard-won weight loss. And I'm referring here to people who did not revert (or perhaps never even indulged in) the fast-food lifestyle. Once again, I refer you to Andrea's comments: fresh, unprocessed food, eaten in moderation, coupled with regular, vigorous exercise...leading to weight re-gain unless caloric intake is consciously and constantly restricted.

I have a number of questions: Are some of us innately more prone to easy gain weight, no matter what our eating profile? If you are, shall we say, naturally on the heavy side, will a "clean" eating regimen only somewhat mitigate your overweight state or just slow down your return to being overweight? Is this propensity exacerbated by a lifetime of dieting, in other words, training our bodies to only maintain the new, lower weight in a semi-starved environment? What is dieting doing to our metabolism?

I am always distressed to read about bloggers who have thought they had graduated to "normal" eating, only to find that they were packing on the pounds as soon as they departed from significant caloric restriction. I'm not talking about people who have gone from perfect dieting to out of control binging. Just people like Andrea.

3 comments:

This is a complicated issue, even though many of us might wish it were simple. I'm glad you approach it with an attitude of curiosity rather than judgement. Metabolism is complex, with many determinants and influences. Ongoing lack of adequate sleep, chronic stress, depression, and inactivity related to sedentary work can all contribute to metabolic resistance. Studies of people who suffered from anorexia or food insecurity show that metabolism slows with long term caloric restriction but eventually returns to previous levels. In general. But there are few definitive studies from which to draw sound conclusions! Whether we are restricting to lose weight or researching weight loss, or trying to understand the links between health and weight, we all seem to be feeling our way in the dark.

My life is a kind of science experiement. For several years I was unable to lose weight. That was during a time of extreme stress, including chronic sleep deprivation (which turned into chronic insomnia) and enforced swallowing of cultural bullsh*t (indoctrination into our US health care system during college). Since graduating, entering menopause, becoming poor and increasingly disabled, losing health insurance, experiencing major life changes beyond what I thought was even a possibility, I have continued to lose weight. What is different?

Mostly, I now have time to sleep (not always easy) and my mind is free. I am not jumping through hoops on command (to earn grades) and behaving in culturally sanctioned ways that I know in my heart are dysfunctional, unethical and crazy-making. Thus, the struggle I face now involves a different kind of stress. As hard as my life is today, I realize now that oppression of the mind is the worst kind of stress there is--at least for me. It causes my body to hunker down and defend itself, and that includes a slower metabolism, decreased immune function, and an increased impulses to eat, all of which contributed to my body's resistance to weight loss.

I intentionally phrased my final words as questions. There doesn't seem to be any definitive answer on metabolism and weight loss. I did a lot of reading and really couldn't seem to put together anything coherent from all the scholarly articles I came upon.

You are so right with respect to the other factors that perhaps serve to slow down metabolism, in particular stress. But then we must ask ourselves, why do some people gain weight under extremely stressful conditions while others waste away?

Questions seem to beget even more questions.

My husband went back to university for a Master's degree several years ago. During one of his classes, he put up his hand and said to the prof, "Professor X. I have a question," to which his prof responded, "I too have many questions."

I found peace on this issue when I reconciled myself to the reality that life is simply unfair on this front. One man's "restriction" is another man's "healthy number of calories." One of the problems with all of the number generators out there telling you what your BMR is if you are X in height, X in weight and of X age is that they make people believe that we can all be lumped into averages and that these numbers apply to us. Clearly, it does not work that way.

I don't look at the future as a lifetime of caloric restriction so much as a lifetime of operating within whatever values work for my body (where I neither gain nor lose weight once I reach my healthy target weight). This is not restriction *for me*, it is the value my body requires.

It is hard not to see my possible future lot as one in which I'm deprived more than other people because I have spent so much of my life extracting pleasure and emotional value from food. Food is, after all, an important source of pleasure for humans and a cultural focal point. It's value aside from mere energy and nutrition is not to be dismissed. However, the volume is the important point. I can still enjoy a small piece of cake, a bite of chocolate or two or three potato chips. I don't have to give it all up, I only have to give up high volume.

So, I think we need to reconcile the fact that life is not fair in this way and some people can have much more food pleasure than others. This isn't some injustice, but merely random biology, and we all get hit with random biological unfairness (like I have a congenital spinal condition, you have your arthritis and joint issues). It would, of course, be helpful if the attitude toward people with weight issues were less punitive and more understanding. If people didn't think we were fat, lazy pigs for being overweight and recognized that we have to choose a more restricted path than them for the same result, this unfairness could be dealt with with more patience and understanding.

The thing that has really helped me come to terms with this and accept it very peacefully is that role of the genetic dice that makes me fat more easily than other people also rolled in my favor in a variety of other ways. I have intelligence, insight, and talent. Other people didn't get the same high roles on these factors. So, it's all pretty unequal, and I should be grateful that at least some things have really gone to my benefit even though the food and weight issue dramatically has not.